Confronting an influenza pandemic with inexpensive generic agents: can it be done?

Statins for the prevention of cardiovascular events associated with avian influenza: the COVID-19 pandemic as a reference

There is growing concern that the severe respiratory disease in birds (avian influenza or 'bird flu') caused by the H5N1 influenza virus, might potentially spread more widely to humans and cause a pandemic. Here we discuss clinical issues related to human infections by the highly pathogenic H5N1 subtype of the avian influenza A virus and make a clinical comparison with recent information obtained from studies of SARS-CoV-2 infection. Firstly, we consider the potential increase in cardiovascular events in humans infected with the H5N1 virus. Like SARS-CoV-2 infection, H5N1 infection may result in endothelial dysfunction and the associated procoagulant and prothrombotic state, and via this mechanism, the infection can potentially increase cardiovascular morbidity, especially in vulnerable individuals with pre-existing cardiovascular disease. Secondly, we discuss the potential beneficial role of statin use, both in the prophylaxis and the treatment of individuals with influenza A(H5N1), as was found favorable for the treatment of COVID-19 caused by SARS-CoV-2 infection.

Antiviral Activity of Angelica Tenuissima Nakai against Influenza A Virus

The influenza A virus poses a serious threat to human health and is an important global public health issue. The drugs currently used for treatment are becoming increasingly ineffective against influenza A viruses and require the development of new antiviral drugs. Angelica tenuissima Nakai (ATN), a traditional herbal medicine belonging to the Umbelliferae family, exhibits a broad range of pharmacological activities, including inflammation, headache, and cold symptoms. In the present study, based on target protein identification, functional enrichment analysis, and gene set comparisons, we first suggested that ATN has potential therapeutic effects against influenza A virus infection. Next, methylthiazol tetrazolium (MTT) and sulforhodamine B colorimetric (SRB) assay results revealed that ATN exhibited low cytotoxicity in Madin-Darby canine kidney (MDCK) cells. The antiviral properties of ATN were observed against H1N1 and H3N2 virus strains. Microscopy confirmed the increased survival rate of the host cells. Further time-of-addition experiments revealed that the addition of ATN before virus adsorption showed similar results to the whole period of treatment. The pre- and co-treated groups showed lower levels of viral RNA (M1 protein). The results of this study suggest that ATN exhibits antiviral properties against the influenza A virus. These therapeutic properties of ATN can serve as a theoretical basis for further research on the applicability of ATN in the development of antiviral agents.

Treating COVID-19: Targeting the Host Response, Not the Virus

In low- and middle-income countries (LMICs), inexpensive generic drugs like statins, ACE inhibitors, and ARBs, especially if used in combination, might be the only practical way to save the lives of patients with severe COVID-19. These drugs will already be available in all countries on the first pandemic day. Because they target the host response to infection instead of the virus, they could be used to save lives during any pandemic. Observational studies show that inpatient statin treatment reduces 28–30-day mortality but randomized controlled trials have failed to show this benefit. Combination treatment has been tested for antivirals and dexamethasone but, with the exception of one observational study in Belgium, not for inexpensive generic drugs. Future pandemic research must include testing combination generic drug treatments that could be used in LMICs.

Modulating cholesterol-rich lipid rafts to disrupt influenza A virus infection

Influenza A virus (IAV) is widely disseminated across different species and can cause recurrent epidemics and severe pandemics in humans. During infection, IAV attaches to receptors that are predominantly located in cell membrane regions known as lipid rafts, which are highly enriched in cholesterol and sphingolipids. Following IAV entry into the host cell, uncoating, transcription, and replication of the viral genome occur, after which newly synthesized viral proteins and genomes are delivered to lipid rafts for assembly prior to viral budding from the cell. Moreover, during budding, IAV acquires an envelope with embedded cholesterol from the host cell membrane, and it is known that decreased cholesterol levels on IAV virions reduce infectivity. Statins are commonly used to inhibit cholesterol synthesis for preventing cardiovascular diseases, and several studies have investigated whether such inhibition can block IAV infection and propagation, as well as modulate the host immune response to IAV. Taken together, current research suggests that there may be a role for statins in countering IAV infections and modulating the host immune response to prevent or mitigate cytokine storms, and further investigation into this is warranted.

In vitro anti-influenza assessment of anionic compounds ascorbate, acetate and citrate

BACKGROUND

Influenza A virus (IAV) infection remains a serious public health threat. Due to drug resistance and side effects of the conventional antiviral drugs, repurposing the available natural compounds with high tolerability and fewer side effects has attracted researchers' attention. The aim of this study was to screen in vitro anti-influenza activity of three anionic compounds ascorbate, acetate, and citrate.

METHODS

The non-cytotoxic concentration of the compounds was determined by MTT assay and examined for the activity against IAV in simultaneous, pre-, and post-penetration combination treatments over 1 h incubation on Madin-Darby Canine Kidney (MDCK) cell line. The virus titer and viral load were determined using hemagglutination assay (HA) and qPCR, respectively. Few pro-inflammatory and anti-inflammatory cytokines were evaluated at RNA and protein levels by qPCR and ELISA, respectively.

RESULTS

The non-cytotoxic concentrations of the ascorbate (200 mg/ml), acetate and citrate (both 3 mg/ml) reduced the viral titer by 6.5, 4.5, and 1.5 logs in the simultaneous combination treatment. The M protein gene copy number decreased significantly in simultaneous treatment (P < 0.01). The expression of cytokines was also affected by the treatment of these compounds.

CONCLUSIONS

These anionic compounds could affect the influenza virus load, thereby reducing pro-inflammatory cytokines and increasing anti-inflammatory cytokines levels.

The effect of statins on the prevalence and mortality of influenza virus infection: a systematic review and meta-analysis

INTRODUCTION

Influenza virus infection is associated with high morbidity and mortality, and so additional therapeutic strategies to reduce the burden for healthcare systems are needed. Statins, by virtue of their anti-inflammatory and immunomodulatory effects, have been hypothesized as capable of influencing the host's response against the influenza virus. The aim of this meta-analysis was to assess the effect of ongoing statin treatment on susceptibility to influenza virus infection and on influenza-associated mortality.

MATERIAL AND METHODS

Studies investigating the impact of statin treatment on influenza prevalence and mortality were searched for in the PubMed-Medline, Scopus, ISI Web of Knowledge, Embase, Proquest, OVID, EBSCO, and CINAHL databases (up to 8 November 2021). Fixed- and random-effects models and the generic inverse variance method were used for quantitative data synthesis.

RESULTS

In the meta-analysis of 14 arms of 2 eligible studies, including 14,997 flu-vaccinated and unvaccinated patients, treatment with statins was associated with a reduction of influenza virus prevalence (odds ratio (OR) = 0.85, 95% confidence interval (CI): 0.73-0.99; p = 0.040). No significant effect of statins on the susceptibility to influenza infection was observed in the distinct communities of either vaccinated or unvaccinated subjects. Among 9 arms of 6 eligible studies, including 87,204 patients, the use of statins among patients with influenza was associated with a reduced mortality (OR = 0.68, 95% CI: 0.56, 0.82; p < 0.001). This result was confirmed for both 30-day mortality since influenza infection diagnosis (OR = 0.61, 95% CI: 0.47, 0.80; p <0.001) and for up to 90-day mortality (OR = 0.74, 95% CI: 0.55, 1.00; p = 0.042).

CONCLUSIONS

Reduced influenza prevalence and increased survival from influenza infection was observed in patients on ongoing statin treatment. Further research is needed to define the possible role of statins as adjunctive therapy in patients with influenza infection.

Potential antiviral effects of some native Iranian medicinal plants extracts and fractions against influenza A virus

Background

Influenza A virus (IAV) infection is a continual threat to the health of animals and humans globally. Consumption of the conventional drugs has shown several side effects and drug resistance. This study was aimed to screen some Iranian medicinal plants extracts and their fractions against influenza A virus.

Methods

Glycyrrhiza glabra (rhizome), Myrtus  commonis (leaves), Melissa officinalis (leaves), Hypericum perforatum (aerial parts), Tilia platyphyllos (flower), Salix alba (bark), and Camellia sinensis (green and fermented leaves) were extracted with 80% methanol and fractionated with chloroform and methanol, respectively. The cytotoxicity of the compounds were determined by MTT colorimetric assay on MDCK cells. The effective concentrations (EC₅₀) of the compounds were calculated from the MTT results compared to the negative control with no significant effects on cell viability. The effects of EC₅₀ of the compounds on viral surface glycoproteins and viral titer were tested by HI and HA virological assays, respectively and compared with oseltamivir and amantadine. Preliminary phytochemical analysis were done for promising anti-IAV extracts and fractions.

Results

The most effective samples against IAV titer (P ≤ 0.05) were crude extracts of G. glabra, M. officinalis and S. alba; methanol fractions of M. communis and M. officinalis; and chloroform fractions of M. communis and C. sinensis (fermented) mostly in co- and pre-penetration combined treatments. The potential extracts and fractions were rich in flavonoids, tannins, steroids and triterpenoids.

Conclusion

The outcomes confirmed a scientific basis for anti-influenza A virus capacity of the extracts and fractions from the selected plants for the first time, and correlated their effects with their phytochemical constituents. It is worth focusing on elucidating pure compounds and identifying their mechanism(s) of action.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03423-x.

Lipid homeostasis and mevalonate pathway in COVID-19: Basic concepts and potential therapeutic targets

Despite encouraging progresses achieved in the management of viral diseases, efficient strategies to counteract infections are still required. The current global challenge highlighted the need to develop a rapid and cost-effective strategy to counteract the SARS-CoV-2 pandemic. Lipid metabolism plays a crucial role in viral infections. Viruses can use the host lipid machinery to support their life cycle and to impair the host immune response. The altered expression of mevalonate pathway-related genes, induced by several viruses, assures survival and spread in host tissue. In some infections, statins, HMG-CoA-reductase inhibitors, reduce cholesterol in the plasma membrane of permissive cells resulting in lower viral titers and failure to internalize the virus. Statins can also counteract viral infections through their immunomodulatory, anti-inflammatory and anti-thrombotic effects. Beyond statins, interfering with the mevalonate pathway could have an adjuvant effect in therapies aimed at mitigating endothelial dysfunction and deregulated inflammation in viral infection. In this review we depicted the historical and current evidence highlighting how lipid homeostasis and mevalonate pathway targeting represents a valid approach to rapidly neutralize viruses, focusing our attention to their potential use as effective targets to hinder SARS-CoV-2 morbidity and mortality. Pros and cons of statins and Mevalonate-pathway inhibitors have been also dissected.

Association of the host genetic factors, hypercholesterolemia and diabetes with mild influenza in an Iranian population

BACKGROUND

Variation in host genetic factors may result in variation in the host immune response to the infection. Some chronic diseases may also affect individuals' susceptibility to infectious diseases. The aim of this study was to evaluate the association of the host genetic factors mostly involved in inflammation, as well as hypercholesterolemia and diabetes with mild flu in an Iranian population.

METHODS

In this cross-sectional study, nasopharyngeal swab samples were collected from 93 patients referred to primary care centers of Markazi, Semnan, and Zanjan provinces (central Iran) due to flu-like symptoms between March 2015 and December 2018. Of these, PCR test identified 49 influenza A/H1N1 and 44 flu-negative individuals. Twelve single-nucleotide polymorphisms (SNPs) in RPAIN, FCGR2A, MBL-2, CD55, C1QBP, IL-10, TNF-α and an unknown gene were genotyped using iPLEX GOLD SNP genotyping analysis. Hypercholesterolemia and diabetes status was determined based on the physician diagnosis. Association of the host genetic variants, hypercholesterolemia and diabetes with mild A/H1N1 flu was assessed with univariable and multivariable logistic regression analysis as implemented in Stata software (v.14). Statistical tests were considered as significant at 0.05 levels.

RESULTS

Frequency of diabetes and hypercholesterolemia, as well as participants mean age was significantly higher in the flu-negative rather than the flu-positive group. Of 12 SNPs, nine did not show any significant association with mild flu in our study (rs1801274, rs1800451, rs2564978, rs361525, rs1800450, rs1800871, rs1800872, rs1800896, rs1800629). Possessing G vs. A allele in two SNPs (rs3786054 and rs8070740) was associated with a threefold increase in the chance of mild flu when compared to flu-negative patients (95% CI: 1.1, 22.0). Possessing C allele (vs. A) in the rs9856661 locus also increased the chance of mild flu up to 2 folds (95% CI: 1.0, 10.0).

CONCLUSION

The results showed that possessing the G allele in either rs3786054 or rs8070740 loci in C1QBP and RPAIN genes, respectively, increased the risk of H1N1 infection up to 3.3 folds, regardless of the patient's age, BMI, diabetes, and hypercholesterolemia. Complementary functional genomic studies would shed more light on the underlying mechanism of human immunity associated with these genetic markers. The identified genetic factors may have the same role in susceptibility to similar respiratory infections with RNA viruses, like SARS, MERS and COVID-19. Future genetic association studies targeting these RNA viruses, especially COVID-19 is recommended. Studies on other ethnic groups would also shed light on possible ethnic variations in genetic susceptibility to respiratory RNA viruses. Trial registry IR.PII.REC.1399.063.

COVID-19, host response treatment, and the need for political leadership

Health officials and scientists have warned that we face the threat of a potentially devastating influenza pandemic. Instead, we are now in the midst of a global coronavirus (COVID-19) pandemic. National and international pandemic preparedness plans have focused on developing vaccines and antiviral treatments. Another way to confront the COVID-19 pandemic (and future pandemics) might be to treat patients with inexpensive and widely available generic drugs that target the host response to infection, not the virus itself. The feasibility of this idea was tested during the Ebola outbreak in West Africa in 2014. This experience should inform our approach to treating COVID-19 patients. It could also save lives during outbreaks of other emerging infectious diseases and episodes of everyday acute critical illness. If this "bottom up" syndromic approach to treating acute critical illness were shown to be effective, it could have a dramatic impact on health, equity and security throughout the world. HIGHLIGHTS: Uncertainty about the outcome of COVID-19 is driving the social, economic and political distress associated with the pandemic. Treating the host response to COVID-19 with inexpensive and widely available generic drugs might save lives and mitigate this distress. Undertaking research on this idea will require political leadership.

Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus

The medical burden caused by respiratory manifestations of influenza virus (IV) outbreak as an infectious respiratory disease is so great that governments in both developed and developing countries have allocated significant national budget toward the development of strategies for prevention, control, and treatment of this infection, which is seemingly common and treatable, but can be deadly. Frequent mutations in its genome structure often result in resistance to standard medications. Thus, new generations of treatments are critical to combat this ever-evolving infection. Plant materials and active compounds have been tested for many years, including, more recently, active compounds like flavonoids. Quercetin is a compound belonging to the flavonols class and has shown therapeutic effects against influenza virus. The focus of this review includes viral pathogenesis as well as the application of quercetin and its derivatives as a complementary therapy in controlling influenza and its related symptoms based on the targets. We also touch on the potential of this class of compounds for treatment of SARS-COV-2, the cause of new pandemic.

Oral disease-modifying antirheumatic drugs and immunosuppressants with antiviral potential, including SARS-CoV-2 infection: a review

There have been several episodes of viral infection evolving into epidemics in recent decades, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the latest example. Its high infectivity and moderate mortality have resulted in an urgent need to find an effective treatment modality. Although the category of immunosuppressive drugs usually poses a risk of infection due to interference of the immune system, some of them have been found to exert antiviral properties and are already used in daily practice. Recently, hydroxychloroquine and baricitinib have been proposed as potential drugs for SARS-CoV-2. In fact, there are other immunosuppressants known with antiviral activities, including cyclosporine A, hydroxyurea, minocycline, mycophenolic acid, mycophenolate mofetil, leflunomide, tofacitinib, and thalidomide. The inherent antiviral activity could be a treatment choice for patients with coexisting rheumatological disorders and infections. Clinical evidence, their possible mode of actions and spectrum of antiviral activities are included in this review article.

LAY SUMMARY

Immunosuppressants often raise the concern of infection risks, especially for patients with underlying immune disorders. However, some disease-modifying antirheumatic drugs (DMARDs) with inherent antiviral activity would be a reasonable choice in the situation of concomitant viral infections and flare up of autoimmune diseases. This review covers DMARDs of treatment potential for SARS-CoV-2 in part I, and antiviral mechanisms plus trial evidence for viruses other than SARS-CoV-2 in part II.

Influenza Hemagglutinin Modulates Phosphatidylinositol 4,5-Bisphosphate Membrane Clustering

The lipid phosphatidylinositol 4,5-bisphosphate (PIP2) forms nanoscopic clusters in cell plasma membranes; however, the processes determining PIP2 mobility and thus its spatial patterns are not fully understood. Using super-resolution imaging of living cells, we find that PIP2 is tightly colocalized with and modulated by overexpression of the influenza viral protein hemagglutinin (HA). Within and near clusters, HA and PIP2 follow a similar spatial dependence, which can be described by an HA-dependent potential gradient; PIP2 molecules move as if they are attracted to the center of clusters by a radial force of 0.079 ± 0.002 pN in HAb2 cells. The measured clustering and dynamics of PIP2 are inconsistent with the unmodified forms of the raft, tether, and fence models. Rather, we found that the spatial PIP2 distributions and how they change in time are explained via a novel, to our knowledge, dynamic mechanism: a radial gradient of PIP2 binding sites that are themselves mobile. This model may be useful for understanding other biological membrane domains whose distributions display gradients in density while maintaining their mobility.

Immunomodulatory properties of quercetin-3-O-α-L-rhamnopyranoside from Rapanea melanophloeos against influenza a virus

BACKGROUND

Influenza infection is a major public health threat. The role of influenza A virus-induced inflammatory response in severe cases of this disease is widely recognized. Drug resistance and side effects of chemical treatments have been observed, resulting in increased interest in alternative use of herbal medications for prophylaxis against this infection. The South African medicinal plant, Rapanea melanophloeos (RM) (L.) Mez of the family Myrsinaceae was selected owing to its traditional use for the treatment of several diseases such as respiratory ailments and also previous preliminary studies of anti-influenza activity of its methanolic extract. The aim of this study was to investigate the immunomodulatory properties of a glycoside flavone isolated from RM against influenza A virus.

METHODS

The non-cytotoxic concentration of the quercetin-3-O-α-L-rhamnopyranoside (Q3R) was determined by MTT assay and tested for activity against influenza A virus (IAV) in simultaneous, pre-penetration and post-penetration combination treatments over 1 h incubation on MDCK cells. The virus titer and viral load targeting NP and M2 viral genes were determined using HA and qPCR, respectively. TNF-α and IL-27 as pro- and anti-inflammatory cytokines were measured at RNA and protein levels by qPCR and ELISA, respectively.

RESULTS

Quercetin-3-O-α-L-rhamnopyranoside at 150 μg/ml decreased the viral titer by 6 logs (p < 0.01) in the simultaneous procedure. The NP and M2 genes copy numbers as viral target genes, calculated based on the Ct values and standard formula, significantly decreased in simultaneous treatment (p < 0.01). The expression of cytokines was also considerably affected by the compound treatment.

CONCLUSIONS

This is the first report of quercetin-3-O-α-L-rhamnopyranoside from RM and its immunomodulatory properties against influenza A virus. Further research will focus on detecting the specific mechanism of virus-host interactions.

South African medicinal plant extracts active against influenza A virus

BACKGROUND

Influenza infection remains a major health threat for animals and humans which crucially requires effective antiviral remedies. The usage of herbal medications as readily available alternatives for their compatibility with the body and fewer side effects compared to synthetic chemical treatments has become popular globally. The aim of this study was to investigate and screen in vitro anti-influenza activity of extracts of five South African medicinal plants, namely Tabernaemontana ventricosa, Cussonia spicata, Rapanea melanophloeos, Pittosporum viridiflorum and Clerodendrum glabrum, species which are used traditionally for the treatment of several diseases such as inflammatory and respiratory diseases.

METHODS

Methanol, ethanol (100% and 30%), acetone, hot and cold water extracts of the powdered plants leaves were obtained by standard methods. The cytotoxicity was determined by the MTT colorimetric assay on MDCK cells. The concentrations below CC₅₀ values were tested for antiviral activity against influenza A virus (IAV) in different combination treatments. The effect of extracts on viral surface glycoproteins and viral titer were tested by HI and HA virological assays, respectively.

RESULTS

Based on the applied methods, the most effective results against IAV were obtained from Rapanea melanophloeos methanol leaf extract (EC₅₀ = 113.3 μg/ml) and Pittosporum viridiflorum methanol, 100% and 30% ethanol and acetone leaf extracts (EC₅₀ values = 3.6, 3.4, 19.2, 82.3 μg/ml, respectively) in all types of combined treatments especially in pre- and post-penetration combined treatments with highly significant effects against viral titer (P ≤ 0.01).

CONCLUSION

The outcomes offer for the first time a scientific basis for the use of extracts of Rapanea melanophloeos and Pittosporum viridiflorum against IAV. It is worth focusing on the isolation and identification of effective active compounds and elucidating the mechanism of action from these species. However, Tabernaemontana ventricosa, Cussonia spicata and Clerodendrum glabrum leaf extracts were ineffective in vitro in this study.

Lanthionine Synthetase C-Like 2 Modulates Immune Responses to Influenza Virus Infection

Broad-based, host-targeted therapeutics have the potential to ameliorate viral infections without inducing antiviral resistance. We identified lanthionine synthetase C-like 2 (LANCL2) as a new therapeutic target for immunoinflammatory diseases. To examine the therapeutic efficacy of oral NSC61610 administration on influenza, we infected C57BL/6 mice with influenza A H1N1pdm virus and evaluated influenza-related mortality, lung inflammatory profiles, and pulmonary histopathology. Oral treatment with NSC61610 ameliorates influenza virus infection by down-modulating pulmonary inflammation through the downregulation of TNF-α and MCP-1 and reduction in the infiltration of neutrophils. NSC61610 treatment increases IL10-producing CD8+ T cells and macrophages in the lungs during the resolution phase of disease. The loss of LANCL2 or neutralization of IL-10 in mice infected with influenza virus abrogates the ability of NSC61610 to accelerate recovery and induce IL-10-mediated regulatory responses. These studies validate that oral treatment with NSC61610 ameliorates morbidity and mortality and accelerates recovery during influenza virus infection through a mechanism mediated by activation of LANCL2 and subsequent induction of IL-10 responses by CD8+ T cells and macrophages in the lungs.

Progress of small molecular inhibitors in the development of anti-influenza virus agents

The influenza pandemic is a major threat to human health, and highly aggressive strains such as H1N1, H5N1 and H7N9 have emphasized the need for therapeutic strategies to combat these pathogens. Influenza anti-viral agents, especially active small molecular inhibitors play important roles in controlling pandemics while vaccines are developed. Currently, only a few drugs, which function as influenza neuraminidase (NA) inhibitors and M2 ion channel protein inhibitors, are approved in clinical. However, the acquired resistance against current anti-influenza drugs and the emerging mutations of influenza virus itself remain the major challenging unmet medical needs for influenza treatment. It is highly desirable to identify novel anti-influenza agents. This paper reviews the progress of small molecular inhibitors act as antiviral agents, which include hemagglutinin (HA) inhibitors, RNA-dependent RNA polymerase (RdRp) inhibitors, NA inhibitors and M2 ion channel protein inhibitors etc. Moreover, we also summarize new, recently reported potential targets and discuss strategies for the development of new anti-influenza virus drugs.

Targeting endosomal acidification by chloroquine analogs as a promising strategy for the treatment of emerging viral diseases

Emerging viruses such as HIV, dengue, influenza A, SARS coronavirus, Ebola, and other viruses pose a significant threat to human health. Majority of these viruses are responsible for the outbreaks of pathogenic lethal infections. To date, there are no effective therapeutic strategies available for the prophylaxis and treatment of these infections. Chloroquine analogs have been used for decades as the primary and most successful drugs against malaria. Concomitant with the emergence of chloroquine‐resistant Plasmodium strains and a subsequent decrease in the use as antimalarial drugs, other applications of the analogs have been investigated. Since the analogs have interesting biochemical properties, these drugs are found to be effective against a wide variety of viral infections. As antiviral action, the analogs have been shown to inhibit acidification of endosome during the events of replication and infection. Moreover, immunomodulatory effects of analogs have been beneficial to patients with severe inflammatory complications of several viral diseases. Interestingly, one of the successful targeting strategies is the inhibition of HIV replication by the analogs in vitro which are being tested in several clinical trials. This review focuses on the potentialities of chloroquine analogs for the treatment of endosomal low pH dependent emerging viral diseases.

Pharmacological intervention for dengue virus infection

Dengue virus (DENV) infection has a considerable health impact in tropical and subtropical countries worldwide. Escalation of infection rates greatly increases morbidity and mortality, most commonly from deaths due to dengue hemorrhagic fever and dengue shock syndrome. Although the development of an effective, long-lasting vaccine has been a major aim for control and prevention of DENV infection, the currently licensed vaccine has limitations and is less than satisfactory. Thus, there remains an important need to identify effective and tolerable medications for treatment of DENV-infected patients both in the early phase, to prevent progression to fatal outcomes, and to minimize deaths after patients develop severe complications. This review will address several specific points, including (1) approaches to identify anti-DENV medications, (2) recent advances in the development of potential compounds targeting DENV infection, (3) experience with clinical trials of regimens for DENV infection, (4) some available medications of potential for clinical trials against DENV infection, (5) reasons for unsuccessful outcomes and challenges of anti-DENV treatments, and (6) directions for developing or selecting better anti-DENV strategies. This review provides useful guidance for clinicians selecting drugs for DENV-infected patients with severe manifestations or potential fatal disease progression, and for basic researchers seeking to develop effective anti-DENV regimens.

Statins for influenza and pneumonia

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The objective of this review is to assess the efficacy and safety of statins in people with influenza and pneumonia. Comparisons will be made between people who have received statin therapy with those who have not received any statin therapy. This review will explore the following questions.

Do statins reduce mortality from influenza and pneumonia? Do statins reduce morbidity and severity of influenza and pneumonia? How safe is it to administer statins to people with influenza and pneumonia?

Edible bird's nest modulate intracellular molecular pathways of influenza A virus infected cells

BACKGROUND

Edible Bird's Nest (EBN) as a popular traditional Chinese medicine is believed to have health enhancing and antiviral activities against influenza A virus (IAV); however, the molecular mechanism behind therapeutic effects of EBN is not well characterized.

METHODS

In this study, EBNs that underwent different enzymatic preparation were tested against IAV infected cells. 50% cytotoxic concentration (CC50) and 50% inhibitory concentration (IC50) of the EBNs against IAV strain A/Puerto Rico/8/1934(H1N1) were determined by HA and MTT assays. Subsequently, the sialic acid content of the used EBNs were analyzed by fluorometric HPLC. Western Blotting and immunofluorescent staining were used to investigate the effects of EBNs on early endosomal trafficking and autophagy process of influenza virus.

RESULTS

This study showed that post inoculations of EBNs after enzymatic preparations have the highest efficacy to inhibit IAV. While CC50 of the tested EBNs ranged from 27.5-32 mg/ml, the IC50 of these compounds ranged between 2.5-4.9 mg/ml. EBNs could inhibit IAV as efficient as commercial antiviral agents, such as amantadine and oseltamivir with different mechanisms of action against IAV. The antiviral activity of these EBNs correlated with the content of N-acetyl neuraminic acid. EBNs could affect early endosomal trafficking of the virus by reducing Rab5 and RhoA GTPase proteins and also reoriented actin cytoskeleton of IAV infected cells. In addition, for the first time this study showed that EBNs can inhibit intracellular autophagy process of IAV life cycle as evidenced by reduction of LC3-II and increasing of lysosomal degradation.

CONCLUSIONS

The results procured in this study support the potential of EBNs as supplementary medication or alternative to antiviral agents to inhibit influenza infections. Evidently, EBNs can be a promising antiviral agent; however, these natural compounds should be screened for their metabolites prior to usage as therapeutic approach.

Pediatric Statin Administration: Navigating a Frontier with Limited Data

Increasingly, children and adolescents with dyslipidemia qualify for pharmacologic intervention. As they are for adults, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) are the mainstay of pediatric dyslipidemia treatment when lifestyle modifications have failed. Despite the overall success of these drugs, the magnitude of variability in dose-exposure-response profiles contributes to adverse events and treatment failure. In children, the cause of treatment failures remains unclear. This review describes the updated guidelines for screening and management of pediatric dyslipidemia and statin disposition pathway to assist the provider in recognizing scenarios where alterations in dosage may be warranted to meet patients' specific needs.

The role of statins in the setting of HIV infection

HIV-infected individuals are at an increased risk of cardiovascular disease (CVD) and other HIV-related co-morbidities. This is due in part to dyslipidemia associated with antiretroviral therapy and increased inflammation and immune activation from chronic HIV infection. Statins not only have potent lipid-lowering properties but are also anti-inflammatory and immunomodulators. Studies suggest that statin therapy in the HIV-infected population may decrease the risk of CVD and other non-AIDS-defining co-morbidities. This review summarizes the recent literature on statin use in the HIV setting.

Chloroquine enhances replication of influenza A virus A/WSN/33 (H1N1) in dose-, time-, and MOI-dependent manners in human lung epithelial cells A549

Anti-malaria drug, chloroquine, has been reported to be effective against influenza A virus (IAV) in vitro and used in in-vivo experiments and clinical trial for prevention or treatment of influenza. In this study, it has been shown by immunofluorescence, hemagglutination, and plaque assays that chloroquine enhanced A/WSN/33 (H1N1) replication with pronounced cytopathic effect in dose-, time-, and MOI-dependent manners in human lung epithelial cells A549. Time-of-addition assay showed that inhibitory effect on virus replication by chloroquine pre-treatment was indistinctive, and virus productions were enhanced when the drug was applied after viral adsorption. The effectiveness of chloroquine as an anti-influenza drug is questioned, and caution in its use is recommended.

Mechanisms of action and efficacy of statins against influenza

The influenza virus (IV) is known to be a resistant virus with frequent mutations, causing severe respiratory diseases in the upper respiratory system. Public health concerns about clinical efficacy of all conventional drugs are ambiguous; therefore, finding additional therapeutic agents is critical to prevent and control influenza outbreaks. Influenza is associated with the induction of proinflammatory cytokines. Scientists have reported that anti-inflammatory drugs, with pleiotropic effects, reduce the burden of severe influenza diseases. Therefore, statins, which are cardioprotective drugs with anti-inflammatory and immunomodulatory effects, may help patients suffering from influenza virus (IV). This review delineates the potential use of statins as an alternative therapy in treating influenza related illness.

Lipidomics identifies a requirement for peroxisomal function during influenza virus replication

Influenza virus acquires a host-derived lipid envelope during budding, yet a convergent view on the role of host lipid metabolism during infection is lacking. Using a mass spectrometry-based lipidomics approach, we provide a systems-scale perspective on membrane lipid dynamics of infected human lung epithelial cells and purified influenza virions. We reveal enrichment of the minor peroxisome-derived ether-linked phosphatidylcholines relative to bulk ester-linked phosphatidylcholines in virions as a unique pathogenicity-dependent signature for influenza not found in other enveloped viruses. Strikingly, pharmacological and genetic interference with peroxisomal and ether lipid metabolism impaired influenza virus production. Further integration of our lipidomics results with published genomics and proteomics data corroborated altered peroxisomal lipid metabolism as a hallmark of influenza virus infection in vitro and in vivo. Influenza virus may therefore tailor peroxisomal and particularly ether lipid metabolism for efficient replication.

Hydroxychloroquine: a multifaceted treatment in lupus

The efficacy of antimalarials, especially hydroxychloroquine (HCQ), in preventing systemic lupus erythematosus (SLE) flares is well demonstrated. However, many studies show that the percentage of SLE patients treated with HCQ remains low. By blocking the toll-like receptor 7 and 9 in plasmacytoid dendritic cells, HCQ inhibits interferon-alpha production which plays a crucial role in SLE pathogenesis. In addition to reducing damage accrual in SLE patients, HCQ appears to protect against the occurrence of diabetes, thrombotic events, and dyslipidemia. As a consequence, some studies have suggested that HCQ, which is inexpensive, has a protective effect on survival in SLE patients. Thanks to the pharmacokinetic properties of HCQ (long half-life) and to the availability of its blood assay, very low or undetectable blood HCQ concentrations are a valuable marker of non-adherence to treatment, thus adding a new benefit to HCQ prescriptions. The main side effect of HCQ is retinal toxicity. This complication is very rare, but may be potentially severe, thus requiring regular screening. Retinal toxicity remains the only absolute contra-indication of HCQ in adult SLE patients. Other contra-indications are few and rare. During pregnancy and breast-feeding, HCQ continuation is not only allowed but recommended. In conclusion, the risk/benefit ratio of HCQ is excellent. Many now believe that all SLE patients should be offered this treatment.

Simvastatin modulates cellular components in influenza A virus-infected cells

Influenza A virus is one of the most important health risks that lead to significant respiratory infections. Continuous antigenic changes and lack of promising vaccines are the reasons for the unsuccessful treatment of influenza. Statins are pleiotropic drugs that have recently served as anti-influenza agents due to their anti-inflammatory activity. In this study, the effect of simvastatin on influenza A-infected cells was investigated. Based on the MTT cytotoxicity test, hemagglutination (HA) assay and qPCR it was found that simvastatin maintained cell viability and decreased the viral load significantly as compared to virus-inoculated cells. The expression of important pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6 and interferon-γ), which was quantified using ELISA showed that simvastatin decreased the expression of pro-inflammatory cytokines to an average of 2-fold. Furthermore, the modulation of actin filament polymerization was determined using rhodamine staining. Endocytosis and autophagy processes were examined by detecting Rab and RhoA GTPase protein prenylation and LC3 lipidation using western blotting. The results showed that inhibiting GTPase and LC3 membrane localization using simvastatin inhibits influenza replication. Findings of this study provide evidence that modulation of RhoA, Rabs and LC3 may be the underlying mechanisms for the inhibitory effects of simvastatin as an anti-influenza compound.

Pulmonary immune responses to 2009 pandemic influenza A (H1N1) virus in mice

BACKGROUND

Well-characterized mice models will afford a cheaper, easy-handling opportunity for a more comprehensive understanding of 2009 influenza A (H1N1) virus's pathogenesis potential. We aimed to provide a robust description of pulmonary immune responses in the mice infected by the virus.

METHODS

BALB/c mice were inoculated intranasally with A/Beijing/501/2009(H1N1) (BJ501) and A/PR/8/34(H1N1) (PR8) viruses and compared for survival rate, viral replication, and kinetics of pulmonary immune responses.

RESULTS

BJ501 virus replicated less efficiently in the lungs than PR8, and both caused lethal illness in the mice. The transient increases of pulmonary TNF-α 2 days post infection for BJ501 and of INF-γ and IL-10 at 6 days post infection for PR8 were observed. IL-2+ and IL-4+ secreting cells showed significant increase 12 days post infection, while IFN-γ+, IgG+ and IgA+ secreting cells increased 6 days post infection. The different patterns of pulmonary immunological parameters between two viruses were at most seen in IL-6, IL-17 secretion and IgG1/IgG2a ratio.

CONCLUSIONS

The BALB/c mouse is evaluated as a good pathogenic model for studying BJ501 2009 H1N1 virus. The work provided some basic and detailed data, which might be referred when further evaluating innate and adapted pulmonary immune responses and local viral load in mice.

Protective effect of fluvastatin on influenza virus infection

Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and have pleiotropic effects. It has been suggested that statins may be a potential treatment during the next influenza pandemic. In a previous study we found that a statin/caffeine combination protects BALB/c mice against Influenza A, subtypes haemagglutinin type 5 and neuraminidase type 1 (H5N1), H3N2 and H1N1 infection. The effect of statins alone on influenza virus infection, however, is not known. In this study, it was investigated whether fluvastatin is capable of inhibiting influenza A virus replication in vitro. The results demonstrated that the synthesis of viral RNA and protein was affected by fluvastatin treatment. Virus production was markedly reduced when fluvastatin was administered simultaneously with the virus; however, a greater inhibition was observed when fluvastatin was added following viral adsorption. The selectivity index [SI; 50% cytotoxic concentration (CC50)/50% inhibition concentration (IC50)], however, was only 21. It was further demonstrated that fluvastatin protects host cells against influenza-induced inflammation by reducing the production of tumour necrosis factor-α, interleukin 8 and interferon γ. In conclusion, the results demonstrated that fluvastatin exerted a minor inhibitory effect on influenza virus infection, which involved anti-inflammatory activities.

Immunopathogenesis of 2009 pandemic influenza

Three years after the pandemic, major advances have been made in our understanding of the innate and adaptive immune responses to the influenza A(H1N1)pdm09 virus and those responses' contribution to the immunopathology associated with this infection. Severe disease is characterized by early secretion of proinflammatory and immunomodulatory cytokines. This cytokine secretion persisted in patients with severe viral pneumonia and was directly associated with the degree of viral replication in the respiratory tract. Cytokines play important roles in the antiviral defense, but persistent hypercytokinemia may cause inflammatory tissue damage and participate in the genesis of the respiratory failure observed in these patients. An absence of pre-existing protective antibodies was the rule for both mild and severe cases. A role for pathogenic immunocomplexes has been proposed for this disease. Defective T cell responses characterize severe cases of infection caused by the influenza A(H1N1)pdm09 virus. Immune alterations associated with accompanying conditions such as obesity, pregnancy or chronic obstructive pulmonary disease may interfere with the normal development of the specific response to the virus. The role of host immunogenetic factors associated with disease severity is also discussed in this review. In conclusion, currently available information suggests a complex immunological dysfunction/alteration that characterizes the severe cases of 2009 pandemic influenza. The potential benefits of prophylactic/therapeutic interventions aimed at preventing/correcting such dysfunction warrant investigation.

Therapeutics against influenza

Despite 75 years of research into prevention and treatment of influenza, the viruses that cause this disease continue to rank as some of the most important pathogens afflicting humans today. Progress in development of therapeutics for influenza has been slow for much of that time, but has accelerated in pace over the last two decades. Two classes of antiviral medications are used in humans at present, but each has limitations in scope and effectiveness of use. New strategies involving these licensed agents, including alternate forms of delivery and combination therapy with other drugs, are currently being explored. In addition, several novel antiviral compounds are in various clinical phases of development. Together with strategies designed to target the virus itself, new approaches to interrupt host–pathogen interactions or modulate detrimental aspects of the immune response have been proposed. Therapy for influenza will likely undergo substantial changes in the decades to come, evolving with our knowledge of pathogenesis as new approaches become viable and are validated clinically.

Role of Fat-Soluble Vitamins A and D in the Pathogenesis of Influenza: A New Perspective

Reduced exposure to solar radiation, leading to a deficiency of vitamin D and hence impaired innate immunity, has been suggested as a trigger for influenza viral replication and as an explanation of seasonal influenza. Although this hypothesis accounts for many unexplained facts about the epidemiology of influenza, gaps remain in understanding the pathogenesis and manifestations of the disease. Several observations suggest a role for vitamin A compounds (retinoids) in the disease. This paper presents a new model of the etiopathogenesis of influenza, suggesting that host resistance and susceptibility depend importantly on the ratio of vitamin D to vitamin A activity. Retinoid concentrations within normal physiological limits appear to inhibit influenza pathogenesis whereas higher background concentrations (i.e., very low vitamin D : A ratios) increase the risk of severe complications of the disease. There is also evidence that influenza-induced or preexisting liver disease, diabetes, and obesity worsen the severity of infection, possibly via liver dysfunction and alterations in retinoid metabolism. The model could be tested by determining the presence of retinoids in the secretions of patients with influenza and by studies of retinoid profiles in patients and controls. Potential strategies for prevention and treatment are discussed.

Treating influenza with statins and other immunomodulatory agents

Statins not only reduce levels of LDL-cholesterol, they counteract the inflammatory changes associated with acute coronary syndrome and improve survival. Similarly, in patients hospitalized with laboratory-confirmed seasonal influenza, statin treatment is associated with a 41% reduction in 30-day mortality. Most patients of any age who are at increased risk of influenza mortality have chronic low-grade inflammation characteristic of metabolic syndrome. Moreover, differences in the immune responses of children and adults seem responsible for the low mortality in children and high mortality in adults seen in the 1918 influenza pandemic and in other acute infectious and non-infectious conditions. These differences probably reflect human evolutionary development. Thus the host response to influenza seems to be the major determinant of outcome. Outpatient statins are associated with reductions in hospitalizations and deaths due to sepsis and pneumonia. Inpatient statins are also associated with reductions in short-term pneumonia mortality. Other immunomodulatory agents--ACE inhibitors (ACEIs), angiotensin receptor blockers (ARBs), PPARγ and PPARα agonists (glitazones and fibrates) and AMPK agonists (metformin)--also reduce mortality in patients with pneumonia (ACEIs, ARBs) or in mouse models of influenza (PPAR and AMPK agonists). In experimental studies, treatment has not increased virus replication. Thus effective management of influenza may not always require targeting the virus with vaccines or antiviral agents. Clinical investigators, not systems biologists, have been the first to suggest that immunomodulatory agents might be used to treat influenza patients, but randomized controlled trials will be needed to provide convincing evidence that they work. To guide the choice of which agent(s) to study, we need new types of laboratory research in animal models and clinical and epidemiological research in patients with critical illness. These studies will have crucial implications for global public health. During the 2009 H1N1 influenza pandemic, timely and affordable supplies of vaccines and antiviral agents were unavailable to more than 90% of the world's people. In contrast, statins and other immunomodulatory agents are currently produced as inexpensive generics, global supplies are huge, and they would be available to treat patients in any country with a basic health care system on the first pandemic day. Treatment with statins and other immunomodulatory agents represents a new approach to reducing mortality caused by seasonal and pandemic influenza.

Newer influenza antivirals, biotherapeutics and combinations

This summary provides an overview of investigational antiviral agents for influenza and of future directions for development of influenza therapeutics. While progress in developing clinically useful antiviral agents for influenza has been generally slow, especially with respect to seriously ill and high-risk patients, important clinical studies of intravenous neuraminidase inhibitors, antibodies and drug combinations are currently in progress. The current decade offers the promise of developing small molecular weight inhibitors with novel mechanisms of action, including host-directed therapies, new biotherapeutics and drug combinations, that should provide more effective antiviral therapies and help mitigate the problem of antiviral resistance. Immunomodulatory interventions also offer promise but need to be based on better understanding of influenza pathogenesis, particularly in seriously ill patients. The development of combination interventions, immunomodulators and host-directed therapies presents unique clinical trial design and regulatory hurdles that remain to be addressed.

Dietary abscisic acid ameliorates influenza-virus-associated disease and pulmonary immunopathology through a PPARγ-dependent mechanism

The anti-inflammatory phytohormone abscisic acid (ABA) modulates immune and inflammatory responses in mouse models of colitis and obesity. ABA has been identified as a ligand of lanthionine synthetase C-like 2, a novel therapeutic target upstream of the peroxisome proliferator-activated receptor γ (PPARγ) pathway. The goal of this study was to investigate the immune modulatory mechanisms underlying the anti-inflammatory efficacy of ABA against influenza-associated pulmonary inflammation. Wild-type (WT) and conditional knockout mice with defective PPARγ expression in lung epithelial and hematopoietic cells (cKO) treated orally with or without ABA (100 mg/kg diet) were challenged with influenza A/Udorn (H3N2) to assess ABA's impact in disease, lung lesions and gene expression. Dietary ABA ameliorated disease activity and lung inflammatory pathology, accelerated recovery and increased survival in WT mice. ABA suppressed leukocyte infiltration and monocyte chemotactic protein 1 mRNA expression in WT mice through PPARγ since this effect was abrogated in cKO mice. ABA ameliorated disease when administered therapeutically on the same day of the infection to WT but not mice lacking PPARγ in myeloid cells. We also show that ABA's greater impact is between days 7 and 10 postchallenge when it regulates the expression of genes involved in resolution, like 5-lipoxygenase and other members of the 5-lipoxygenase pathway. Furthermore, ABA significantly increased the expression of the immunoregulatory cytokine interleukin-10 in WT mice. Our results show that ABA, given preventively or therapeutically, ameliorates influenza-virus-induced pathology by activating PPARγ in pulmonary immune cells, suppressing initial proinflammatory responses and promoting resolution.

Effect of statin treatments on highly pathogenic avian influenza H5N1, seasonal and H1N1pdm09 virus infections in BALB/c mice

Statins are used to control elevated cholesterol or hypercholesterolemia, but have previously been reported to have antiviral properties. AIMS: To show efficacy of statins in various influenza virus mouse models. MATERIALS & METHODS: BALB/c mice were treated intraperitoneally or orally with several types of statins (simvastatin, lovastatin, mevastatin, pitavastatin, atorvastatin or rosuvastatin) at various concentrations before or after infection with either influenza A/Duck/ MN/1525/81 H5N1 virus, influenza A/Vietnam/1203/2004 H5N1 virus, influenza A/ Victoria/3/75 H3N2 virus, influenza A/NWS/33 H1N1 virus or influenza A/CA/04/09 H1N1pdm09 virus. RESULTS: The statins administered intraperitoneally or orally at any dose did not significantly enhance the total survivors relative to untreated controls. In addition, infected mice receiving any concentration of statin were not protected against weight loss due to the infection. None of the statins significantly increased the mean day of death relative to mice in the placebo treatment group. Furthermore, the statins had relatively few ameliorative effects on lung pathology or lung weights at day 3 and 6 after virus exposure, although mice treated with simvastatin did have improved lung function as measured by arterial saturated oxygen levels in one experiment. CONCLUSION: Statins showed relatively little efficacy in any mouse model used by any parameter tested.

Attenuation of influenza virus infectivity with herbal-marine compound (HESA-A): an in vitro study in MDCK cells

Background

The influenza virus is still one of the most important respiratory risks affecting humans which require effective treatments. In this case, traditional medications are of interest. HESA-A is an active natural biological compound from herbal-marine origin. Previous studies have reported that the therapeutic properties of HESA-A are able to treat psoriasis vulgaris and cancers. However, no antiviral properties have been reported.

Methods

This study was designed to investigate the potential antiviral properties of HESA-A and its effects in modulating TNF-α and IL-6 cytokine levels. HESA-A was prepared in normal saline as a stock solution (0.8 mg/ml, pH = 7.4). Percentages of cell survival when exposed to different concentrations of HESA-A at different time intervals was determined by MTT assay. To study the potential antiviral activity of HESA-A, Madin-Darby Canine Kidney (MDCK) cells were treated with the effective concentration (EC₅₀) of HESA-A (0.025 mg/ml) and 100 TCID₅₀/0.1 ml of virus sample under different types of exposure.

Results

Based on the MTT method and hemagglutination assay (HA), HESA-A is capable of improving cell viability to 31% and decreasing HA titre to almost 99% in co-penetration exposures. In addition, based on quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), it was found that HESA-A causes decrements in TNF-α and IL-6 cytokine expressions, which was significant for TNF-α (p ≤ 0.05) but not for IL-6.

Conclusion

In conclusion, HESA-A was effective against influenza infection through suppressing cytokine expression.

Genetic screens for the control of influenza virus replication: from meta-analysis to drug discovery

Current anti-influenza virus drugs target two viral proteins and induce a selective pressure for the generation of drug resistant variants. This stresses the need for additional therapeutic strategies including drug targeting of cellular factors that are essential for viral replication. Reverse genetics approaches can be used to identify these factors and recently six independent genomic initiatives have led to the identification of 925 host factors that are essential for the replication of influenza viruses. Here we report a meta-analysis of this dataset, first revealing that these screens are poorly overlapping at the gene level. However, a strong convergence was observed at the level of biological processes which was further supported by an interactomic analysis showing a high interconnectivity of the essential host factors in the human protein network. Plugging virus-host protein interaction data on this dataset reveals a significant targeting of these factors by viral proteins, further validating the cellular targets. Combining this information, the first drug-influenza virus target network was constructed by retrieving from DrugBank 298 molecules interacting with 100 essential host factors. Of these, 204 are FDA-approved offering interesting potential for rapid drug repositioning in the treatment of flu.

Influenza A/H1N1 vaccination of patients with SLE: can antimalarial drugs restore diminished response under immunosuppressive therapy?

OBJECTIVE

To assess the efficacy and safety of pandemic 2009 influenza A (H1N1) in SLE under different therapeutic regimens.

METHODS

A total of 555 SLE patients and 170 healthy controls were vaccinated with a single dose of a non-adjuvanted preparation. According to current therapy, patients were initially classified as SLE No Therapy (n = 75) and SLE with Therapy (n = 480). Subsequent evaluations included groups under monotherapy: chloroquine (CQ) (n = 105), prednisone (PRED) ≥20 mg (n = 76), immunosuppressor (IS) (n = 95) and those with a combination of these drugs. Anti-H1N1 titres and seroconversion (SC) rate were evaluated at entry and 21 days post-vaccination.

RESULTS

The SLE with Therapy group had lower SC compared with healthy controls (59.0 vs 80.0%; P < 0.0001), whereas the SLE No Therapy group had equivalent SC (72 vs 80.0%; P = 0.18) compared with healthy controls. Further comparison revealed that the SC of SLE No Therapy (72%) was similar to the CQ group (69.5%; P = 0.75), but it was significantly reduced in PRED ≥20 mg (53.9%; P = 0.028), IS (55.7%; P = 0.035) and PRED ≥20 mg + IS (45.4%; P = 0.038). The concomitant use of CQ in each of these later regimens was associated with SC responses comparable with SLE No Therapy group (72%): PRED ≥20 mg + CQ (71.4%; P = 1.00), IS + CQ (65.2%; P = 0.54) and PRED ≥20 mg + IS + CQ (57.4%; P = 0.09).

CONCLUSION

Pandemic influenza A H1N1/2009 vaccine response is diminished in SLE under immunosuppressive therapy and antimalarials seems to restore this immunogenicity. Trial registration. www.clinicaltrials.gov, NCT01151644.

Triple combinations of neuraminidase inhibitors, statins and fibrates benefit the survival of patients with lethal avian influenza pandemic

The high mortality of highly pathogenic avian influenza A (H5N1) viruses infection in humans gives rise to considerable concern that it might someday cause another lethal pandemic. At present there is no other effective alternative besides the early and enough administration of neuraminidase inhibitors, which may be crucial for the patient management. However, its efficacy is sometimes limited because of the late administration in some patients especially the seriously ill ones and the continual occurrence of oseltamivir resistant A (H5N1) strains. The specific candidate vaccine are still under development and the practical value of passive immunization is hard to be widely applied because of the scarcity of convalescent human plasma, especially in the early stage of a serious and rapidly progressing pandemic. Statins and fibrates, both of which are used in clinical practice, have anti-inflammatory and immunomodulatory effects and other multiple biologic activities. So we hypothesized that the two immunomodulatory agents may exhibit synergistic effects when they were combined to neuraminidase inhibitors to treat the A (H5N1) viruses infections via inhibiting the production of either the early inflammatory mediators (e.g., many cytokine/chemokine) or the late mediator (e.g., High Mobility Group Box Protein 1), even showing the anti-viral activities with the prevention of the development of antiviral resistance. Therefore, the novel triple combinations may be an optimal management to confront the next lethal influenza pandemic on its very beginning.

Cross clade prophylactic and therapeutic efficacy of polyvalent equine immunoglobulin F(ab')2 against highly pathogenic avian influenza H5N1 in mice

BACKGROUND

Highly pathogenic avian influenza H5N1 virus (HPAI H5N1) has the potential to cause a new pandemic, which may lead to disasters in the world. However, we cannot predict the HPAI H5N1 strain that might cause the pandemic. Therefore, broad-spectrum prophylactic or therapeutic preparations for containment of a possible future pandemic are urgently needed. Polyvalent equine immunoglobulin F(ab')2 may be a promising candidate.

METHODS

We prepared four pepsin digested immunoglobulin F(ab')2 from the horses immunized with purified VNH5N1-Puerto Rico/8/34 (PR8)/CDC-RG (VNRG, Clade 1), A/Indonesia/05/2005(H5N1)-PR8-IBCDC-RG2 (INRG, Clade 2.1), and A/Anhui/01/2005(H5N1)-PR8-IBCDC-RG5 (AHRG, Clade 2.3.4) and PBS (negative control), respectively. The protective effect of the monovalent or polyvalent F(ab')2 against A/Ostrich/SZ/097/04 (clade 0) infection was determined by cytopathic effect (CPE) in cultured Madin-Darby canine kidney (MDCK) cells. The prophylactic and therapeutic efficacy of the polyvalent F(ab')2 was further evaluated by observing survival, weight loss and viral load when the polyvalent F(ab')2 was introduced into mice one day prior to-, three days post-lethal challenge with A/Ostrich/SZ/097/04.

RESULTS

The half neutralization doses (ND50) of purified monovalent equine F(ab')2 prepared by the VNRG, INRG or AHRG-immunized horses and polyvalent one against A/Ostrich/SZ/097/04 were 320, 1280, 1280 and 2560 in cultured MDCK cells, respectively. 10 μg polyvalent F(ab')2 could completely protect mice infected with 100 half lethal doses (LD50) of A/Ostrich/SZ/097/04 in preventive settings. In therapeutic settings, even when injected three days post lethal infection, mice were still completely protected, although 200 μg of polyvalent F(ab')2 was required.

CONCLUSIONS

Our work has provided experimental supports for testing the broad-spectrum protective efficacy of polyvalent equine immunoglobulin F(ab')2 for the future large trials.

Report of the 'mechanisms of lung injury and immunomodulator interventions in influenza' workshop, 21 March 2010, Ventura, California, USA

Please cite this paper as: Howard et al. (2011) Report of the ‘Mechanisms of lung injury and immunomodulator interventions in influenza’ workshop, 21 March 2010, Ventura, California, USA*. Influenza and Other Respiratory Viruses 5(6), 453–e475.

The clinical course of influenza and the extent of lung injury are determined by both viral and host factors, as well as sometimes secondary bacterial infections and exacerbations of underlying conditions. The balance between viral replication and the host immune responses is central to disease pathogenesis, and the extent of lung injury in severe influenza infections may be due in part to overly exuberant or dysregulated innate inflammatory responses or sometimes deficient responses. Acute respiratory distress syndrome (ARDS) is the principal cause of respiratory failure associated with severe influenza. ARDS can be triggered by both direct lung insults (e.g. respiratory pathogens) and systemic insults (e.g. sepsis), and the lung damage is exacerbated by the inflammatory response associated with either infectious or non‐infectious insults. This workshop aimed to review the current understanding of lung injury in acute influenza and describe cellular and molecular mechanisms of lung injury that are common to influenza and infections by other respiratory pathogens. In addition, therapeutic agents that target host response proteins and pathways were identified and investigational agents in development reviewed. A logical strategy would be to combine antiviral treatment with drugs that modify excessive host responses or supplement deficient ones. However, a better understanding of common cell signalling pathways associated with acute lung injury caused by influenza and other pathogens is necessary to understand immunopathologic causes of lung injury. This will help determine which immunomodulatory interventions might be useful, and to predict the appropriate timing and consequences of their use.

Protein glycosylation in infectious disease pathobiology and treatment

A host of bacteria and viruses are dependent on O-linked and N-linked glycosylation to perform vital biological functions. Pathogens often have integral proteins that participate in host-cell interactions such as receptor binding and fusion with host membrane. Fusion proteins from a broad range of disparate viruses, such as paramyxovirus, HIV, ebola, and the influenza viruses share a variety of common features that are augmented by glycosylation. Each of these viruses contain multiple glycosylation sites that must be processed and modified by the host post-translational machinery to be fusogenically active. In most viruses, glycosylation plays a role in biogenesis, stability, antigenicity and infectivity. In bacteria, glycosylation events play an important role in the formation of flagellin and pili and are vitally important to adherence, attachment, infectivity and immune evasion. With the importance of glycosylation to pathogen survival, it is clear that a better understanding of the processes is needed to understand the pathogen requirement for glycosylation and to capitalize on this requirement for the development of novel therapeutics.

Association between use of HMG CoA reductase inhibitors and mortality in HIV-infected patients

INTRODUCTION

HIV infection is a disease associated with chronic inflammation and immune activation. Antiretroviral therapy reduces inflammation, but not to levels in comparable HIV-negative individuals. The HMG-coenzyme A reductase inhibitors (statins) inhibit several pro-inflammatory processes and suppress immune activation, and are a logical therapy to assess for a possible salutary effect on HIV disease progression and outcomes.

METHODS

Eligible patients were patients enrolled in the Johns Hopkins HIV Clinical Cohort who achieved virologic suppression within 180 days of starting a new highly active antiretroviral therapy (HAART) regimen after January 1, 1998. Assessment was continued until death in patients who maintained a virologic suppression, with right-censoring of their follow-up time if they had an HIV RNA > 500 copies/ml. Cox proportional hazards regression was used to assess statin use as a time-varying covariate, as well as other demographic and clinical factors.

RESULTS

A total of 1538 HIV-infected patients fulfilled eligibility criteria, of whom 238 (15.5%) received a statin while taking HAART. There were 85 deaths (7 in statin users, 78 in non-users). By multivariate Cox regression, statin use was associated with a relative hazard of 0.33 (95% CI: 0.14, 0.76; P =  0.009) after adjusting for CD4, HIV-1 RNA, hemoglobin and cholesterol levels at the start of HAART, age, race, HIV risk group, prior use of ART, year of HAART start, NNRTI vs. PI-based ART, prior AIDS-defining illness, and viral hepatitis coinfection. Malignancy, non-AIDS-defining infection and liver failure were particularly prominent causes of death.

DISCUSSION

Statin use was associated with significantly lower hazard of dying in these HIV-infected patients who were being effectively treated with HAART as determined by virologic suppression. Our results suggest the need for confirmation in other observational cohorts, and if confirmed, the need for a clinical trial of statin use in HIV infection.

Current work and future possibilities for the management of severe influenza: using immunomodulatory agents that target the host response

In this article, we argue the case that the excessive inflammatory response seen in severe influenza contributes to severe illness and death by disabling oxidative phosphorylation in mitochondria, leading to reduced cellular levels of ATP. When the mitochondrial permeability transition is induced, cells cannot die by apoptosis in the face of reduced ATP levels, because apoptosis depends upon ATP availability, and so cells undergo necrosis. Cellular necrosis causes release of proinflammatory molecules such as high mobility group box 1 protein and mitochondrial DNA, and these could contribute to the prolongation of inflammation during severe influenza. With these concepts in mind, we discuss how immunomodulatory agents that prevent cellular necrosis (by restoring mitochondrial function) and limit inflammation are promising influenza treatments.

Chloroquine for influenza prevention: a randomised, double-blind, placebo controlled trial

BACKGROUND

Chloroquine has in-vitro activity against influenza and could be an ideal candidate for worldwide prevention of influenza in the period between onset of a pandemic with a virulent influenza strain and the development and widespread dissemination of an effective vaccine. We aimed to assess the efficacy of such an intervention.

METHODS

In this randomised, double-blind, placebo-controlled trial done at a single centre in Singapore, we randomly assigned (1:1) healthy adults to receive chloroquine phosphate (500 mg/day for 1 week, then once a week to complete 12 weeks) or matching placebo by use of a computer-generated randomisation list. Participants filled an online symptom diary every week, supplemented by daily diaries and self-administered nasal swabs when unwell. Haemagglutination-inhibition assays for influenza A (H1N1, H3N2) and B were done on blood samples taken at baseline and after 12 weeks. The primary outcome was laboratory-confirmed clinical influenza defined by specific symptoms accompanied by influenza RNA on nasal swabs or a four-fold increase in haemagglutination-inhibition titres over the 12-week study period. Analysis was by intention to treat. This trial was registered with ClinicalTrials.gov, number NCT01078779.

FINDINGS

From November, 2009, to February, 2010, we recruited 1516 eligible participants. 1496 (96%) returned at week 12 and were included in the efficacy analysis. Adherence to study intervention was 97%, and 94% of the scheduled weekly diaries were completed. Eight (1%) of 738 participants had laboratory-confirmed clinical influenza in the placebo group and 12 (2%) of 724 in the chloroquine group (relative risk 1·53, 95% CI 0·63-3·72; p=0·376). 29 (4%) of 738 had laboratory-confirmed influenza infection (symptomatic or asymptomatic) in the placebo group and 38 (5%) of 724 in the chloroquine group (1·34, 0·83-2·14; p=0·261). 249 (33%) of 759 participants reported adverse events (mostly mild) in the placebo group and 341 (45%) of 757 in chloroquine group (p<0·0001). Headache, dizziness, nausea, diarrhoea, and blurred vision were more common in the chloroquine group, but rarely resulted in treatment discontinuation. One serious adverse event (hepatitis) was possibly related to chloroquine.

INTERPRETATION

Although generally well tolerated by a healthy community population, chloroquine does not prevent infection with influenza. Alternative drugs are needed for large-scale prevention of influenza.

FUNDING

National Medical Research Council, Singapore.